Mariah -

I'd say Daydream because it's a fitting name for the themes and overall sound of the album. Butterfly isn't bad either. Having the Emotions album named as The Wind instead would have been great.
Janet - The Velvet Rope
Whitney - Her album names were also a bit of a mess. Three out of six of her studio albums were just basically her name. And her albums don't really have a cohesive theme, and the other names would just be the name of one of the songs on the album. I guess I'll go with I Look To You